Tissues patches and related delivery systems and methods

ABSTRACT

Endoluminally delivered tissue patches and related systems and methods for delivering the tissue patches for treating lesions of the alimentary tract are disclosed. A system for delivering a tissue implant includes a catheter having an expandable member at a distal end portion, a carrier placed around the expandable member, and the carrier configured to expand from a contracted state to an expanded state and to receive the tissue implant. The tissue implant contacts the lesion of the alimentary tract when the expandable member expands the carrier to the expandable state.

STATEMENT OF RELATED APPLICATION

This is a continuation of application Ser. No. 10/428,801, filed May 5,2003, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to tissue patches and related systems andmethods for delivering the tissue patches. In particular, the presentinvention relates to endoluminally delivered tissue patches fortreating, for example, lesions of the alimentary tract to promotehealing and reduce risk of infection.

BACKGROUND OF THE INVENTION

Gastroesophageal reflux occurs when stomach acid enters the esophagus.This reflux of acid into the esophagus can occur naturally in healthyindividuals, but also may become a pathological condition in others.Effects from gastroesophageal reflux range from mild to severe. Mildeffects include heartburn, a burning sensation experienced behind thebreastbone. More severe effects include a variety of complications, suchas esophageal erosion, esophageal ulcers, esophageal stricture, abnormalepithelium (e.g., Barrett's esophagus), and/or pulmonary aspiration.These various clinical conditions that result from reflux of stomachacid into the esophagus are referred to generally as GastroesophagealReflux Disease (GERD).

Many mechanisms contribute to prevent gastroesophageal reflux in healthyindividuals. One such mechanism is the functioning of the loweresophageal sphincter (LES). FIG. 1A schematically illustrates theesophagus as it would appear in a healthy individual in the region ofthe LES. The LES 1 is a ring of smooth muscle and increased annularthickness existing in approximately the last four centimeters of theesophagus 3. In its resting state, the LES 1 creates a region of highpressure (approximately 15-30 mm Hg above intragastric pressure) at theopening of the esophagus 3 into the stomach 5. This pressure aids inclosing the esophagus 3 so that contents of the stomach cannot pass backinto the esophagus 3. The LES 1 opens in response to swallowing andperistaltic motion in the esophagus 3, allowing food to pass into thestomach 5. After opening, however, a properly functioning LES 1 shouldreturn to the resting, or closed state. Transient relaxations of the LES1 do occur in healthy individuals, typically resulting in occasionalbouts of heartburn. Also, lack of support for the esophagus at the LESor widening of space of the diaphragm that supports the esophagus oftenallows a portion of the gastric fundus to protrude up through theesophagus, resulting in movement of the LES and changing the pressuresseen at the LES region. This condition, generally referred to as hiatalhernias, is common in the elderly and is one of the major contributingfactors in GERD.

Referring to FIG. 1A, the stomach lining 2 is comprised of columnarcells, while the esophageal lining 4 is comprised of squamous cells.These cells are histologically distinct from one another and serve vitalfunctions. For example, while columnar cells are acid resistant,squamous cells are prone to damage by stomach acid. The point at whichthe cell types transition is known as the “Z-line” 6 and is generallylocated in a healthy individual at a point below the LES region 1.However, when a healthy esophagus is subject to repeated, prolongedexposure to stomach acid reflux, the cell structure of the esophageallining 4 changes from the normal squamous cells into the columnar cellsand, as shown in FIG. 1B, “fingers” 7 of columnar cells appear in thearea of the LES 1. The “fingers” 7 of columnar cells, also known asBarrett's Epithelium, can occur in a patient suffering from chronicGERD.

Since an individual with Barrett's epithelial tissue is many times morelikely to develop esophageal cancer than a healthy individual, asurgical resection of the tissue or tissue ablation is often performed.This type of surgical resection of diseased tissue, however, introduceswidely dispersed, open wounds that are very painful to the patient andtake a long time to heal. These wounds may be prone to infection if theacid is not properly managed through appropriate medications. Othertypes of wounds or lesions may also be introduced during the naturalprogression of the disease, which are subject to the same harshcondition present in this part of anatomy.

Therefore, it is accordingly an object of the present invention toprovide devices and related methods for treating lesions in thealimentary tract, such as, for example, endoscopic mucosal resection(EMR) sites or esophagus. In particular, the devices and methods promotehealing of the lesions by stimulating tissues for rapid healing and/orregrowth while reducing the risk of infection and discomfort of thepatient in the least invasive way possible.

In order to eliminate or reduce the need for highly invasive andphysiologically insulting surgical procedures, endoscopic techniqueshave been developed for the diagnosis and/or treatment of certaindisorders. Endoscopy allows examination and the manipulation of toolsand tissues in interior areas of a patient's body utilizing naturallyoccurring orifices in the body, such as the alimentary tract. Endoscopicsurgery eliminates or greatly reduces the need for the large,surgically-produced openings traditionally required to obtain access tosites deep within the body and, thus, reduces the attendant trauma toskin, muscle, and other tissues. Endoscopic surgery also eliminates orgreatly reduces various risks associated with effects of anesthesiaduring a course of surgery. Consequently, a patient may experience lesspain, recover more quickly, and present less scarring.

Therefore, it is accordingly another object of the present invention toprovide devices and related methods for endoluminal delivery of thetreatment device to a lesion of the alimentary tract, which eliminate orreduce the need for highly invasive, physiologically insulting surgicalprocedures.

SUMMARY OF THE INVENTION

In accordance with the purpose of the invention, as embodied and broadlydescribed herein, one aspect of the invention provides a tissue patchfor treatment of a lesion in an alimentary tract of a patient. Thetissue patch includes a tissue implant having a top surface and a bottomsurface, a substrate surrounding the tissue implant such that thesubstrate forms a first layer on the top surface and a second layer onthe bottom surface. The first layer has a first predetermined thicknessand the second layer has a second predetermined thickness different fromthe first predetermined thickness.

According to another aspect of the present invention, a tissue patch fortreatment of a lesion in an alimentary tract of a patient includes atissue implant and a substrate containing the tissue implant. Thesubstrate is formed of a plurality of sections capable of being foldedinto a contracted state for endoluminal delivery to the lesion.

In yet another aspect of the present invention, a system for deliveringa tissue implant to a lesion in an alimentary tract of a patient isprovided. The system includes a catheter having an expandable member ata distal end portion and a carrier having an outer surface and an innersurface and placed around the expandable member. The carrier isconfigured to expand from a contracted state to an expanded state and toreceive the tissue implant. The tissue implant contacts the lesion ofthe alimentary tract when the expandable member expands the carrier tothe expandable state.

[In still another aspect of the present invention, a method ofdelivering a tissue implant to a lesion in a patient's body is provided.The method includes providing a catheter having an expandable member ata distal end portion, disposing a contracted carrier configured toexpand to an expanded state and containing the tissue implant around theexpandable member, inserting the catheter and the contracted carrierinto a lumen containing the lesion, positioning the carrier andexpandable member at the lesion, and expanding the expandable member soas to expand the carrier to the expanded state to implant the tissueimplant into the lesion.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of theinvention and together with the description, serve to explain theprinciples of the invention.

In the drawings:

FIG. 1A is a schematic cross-sectional illustration of a healthyesophagus in the region of the lower esophageal sphincter (LES);

FIG. 1B is a schematic cross-sectional illustration of an esophagus witha pathological condition known as “Barrett's Esophagus” in the region ofthe lower esophageal sphincter (LES);

FIG. 2 is top and cross-sectional side views of a tissue patch accordingto an embodiment of the present invention;

FIG. 3 is top and cross-sectional side views of a tissue patch accordingto another embodiment of the present invention;

FIG. 4A is top and cross-sectional side views of a tissue patchaccording to yet another embodiment of the present invention;

FIG. 4B is a cross-sectional elevation view of a cylindrical tissuepatch formed by curling the rectangular tissue patch shown in FIG. 4Aoutward according to still another embodiment of the present invention;

FIG. 5A is a delivery system for endoluminal delivery of a tissueimplant, with an expandable member in a deflated state according to anembodiment of the present invention;

FIG. 5B is a delivery system for endoluminal delivery of a tissueimplant, with an expandable member in an inflated state according to anembodiment of the present invention;

FIG. 6 is a carrier showing a folded state (top) and an unfolded state(bottom) according to an embodiment of the present invention;

FIGS. 6A-D are expandable carriers showing a partially expanded stateaccording to another embodiment of the present invention;

FIGS. 7A-C are cross-sectional side views of a carrier holding a tissueimplant according to various embodiments of the present invention;

FIG. 8A is a carrier showing a folded state according to anotherembodiment of the present invention;

FIG. 8B is a carrier showing an unfolded state according to anotherembodiment of the present invention;

FIG. 8C is a cross-sectional side view of the carrier shown in FIG. 5B,showing the arrangement of the sections according to an embodiment ofthe present invention;

FIG. 9 is a cross-sectional view of a delivery system including acatheter, an expandable member, a carrier, and a sleeve, with theexpandable member in a deflated state according to an embodiment of thepresent invention;

FIG. 10 is a schematic illustration of a tissue delivery system with anexpandable member deflated in position for deployment in the esophagus;

FIGS. 11A-C are cross-sectional views through a region of an esophagusshowing the delivery system in three stages of inflation within theesophagus according to an embodiment of the present invention;

FIG. 12A is a cross-sectional view through a region of an esophagushaving a diseased tissue before a resection of the diseased tissue isperformed;

FIG. 12B is a cross-sectional view through a region of an esophagusafter a resection of the diseased tissue is performed;

FIG. 12C is a cross-sectional view through a region of an esophagusafter a tissue patch is delivered to the resection site, according to anembodiment of the present invention; and

FIG. 12D is a cross-sectional view through a region of an esophagusshowing a fully healed site.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the exemplary embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

FIG. 2 shows top and cross-sectional views (A-A′) of a tissue patch 10 aaccording to an embodiment of the present invention. Referring to thefigure, the tissue patch 10 a may include a sheet of tissue implant 11a, preferably an engineered tissue (e.g., cultured tissue), embedded ina substrate, such as, for example, bio-absorbable gel 12, which can bedissolved in a patient's body over a period of time. The bottom surface17 a of the tissue patch 10 a may be configured to contact the lesion tobe treated while the top surface 18 a may face a lumen of, for example,the alimentary tract of a patient. The bio-absorbable gel 12 forms a toplayer 16 a on the top surface 14 of the sheet of engineered tissue 11 aand a bottom layer 15 a on the bottom surface 13 of the sheet ofengineered tissue 11 a. The bio-absorbable gel layers 15 a, 16 a areintended to protect the tissue implant 11 a from the harsh conditions inthe lumen of the alimentary tract. In particular, the top layer 16 a mayhave a predetermined thickness which may be greater than a predeterminedthickness of the bottom layer 15 a. This is because the top layer 16 ais intended to protect the tissue implant during the time periodrequired for healing of the lesion (for example, several days), whilethe bottom layer 15 a is intended to protect the tissue only duringinsertion and placement of the patch 10 a in the area of the lesion andquickly dissolve away, allowing layer 11 a to stimulate growth ofhealthy tissue.

The bio-absorbable gel 12 may be cross-linked polymer networks that canbe manufactured to be responsive to temperature, light, pH, and/or anumber of other internal/external stimuli. The gel response to externalstimuli can take the form of variable viscosity, opacity, waterabsorption, permeability, and more. The bio-absorbable gel 12 maycomprise polylactic and/or polyglycolic polymers. The bio-absorbable gel12 may be infused with a number of therapeutic chemistries such as HumanGrowth Hormone (HGH), genetically engineered cells, antibiotics,analgesics or anaesthetics, and/or pH sensitive or reactive chemistry topromote cell growth in the tissue patch and the surrounding esophagealtissue, to relieve pain, prevent infection and hasten the healingprocess.

The area covered by the bio-absorbable gel 12 may be larger than thesurface area of the sheet of tissue 11 a, such that the area of the gel12 containing no tissue forms a circumferential extension 19 to moreeffectively cover the area of the lesion. The area of circumferentialextension 19 may be provided with bio-adhesive material to enhanceattachment of the tissue patch to the lesion. It should be understood,however, that the bio-adhesive material may be applied to areas otherthan the circumferential extension 19 by coating or mixing in thebio-absorbable gel 12. It should also be understood that the tissuepatch may be provided without the circumferential extension 19, as shownin FIG. 3.

In the exemplary embodiments shown in FIGS. 2 and 3, the tissue patches10 a, 10 b are shown to have an oval shape having a length L and a widthW. It should be understood, however, that the patches 10 a, 10 b could,and most likely would, come in a variety of shapes and sizes dependingupon the size and shape of the lesion to be treated. For example, asshown in FIG. 4A, a tissue patch 10 c may be made rectangular. Therectangular tissue patch 10 c may be curled outward to form acylindrical patch used for treatment of a long circumferential lesion ina lumen, as shown in FIG. 4B.

As will be described later in detail, the tissue patches 10 a, 10 b, 10c shown in FIGS. 2, 3, and 4A-B may be configured to be folded into acompact form for an endoluminal deployment onto the site to be treated.In that case, the patches may be folded, for example, along dotted linesshown in FIGS. 3 and 4A. It should also be recognized that tissuepatches 10 a, 10 b, 10 c may be delivered in its original shape withoutfolding into a compact form.

It is another object of the present invention to accurately deliver andattach the tissue implant endoluminally in situ. FIGS. 5A and 5B show adelivery system that may be used for delivering a tissue implant andassociated materials endoluminally to a lesion to be treated, accordingto an exemplary embodiment of the present invention. The delivery systemmay comprise a catheter 30 having a proximal portion 31 and a distalportion 32. An expandable member 35 may be located at the distal portion32 of the catheter 30 and may be configured to expand upon actuation bya suitable actuator (not shown) at the proximal end of catheter 30. Thecatheter 30 may form a circumferential recess (not shown) in the distalportion 32 for receiving the expandable member 35 therein. Thiscircumferential recess may have sufficient width and depth foraccommodating the expandable member 35, so that the catheter 30 may havea substantially uniform outer surface when the expandable member 35 inits deflated state is positioned in the circumferential recess of thecatheter 30. Although the expandable member 35 in this exemplaryembodiment is a balloon 35, it should be understood that the expandablemember 35 may be any other conventionally known expanding device. In thedeflated state shown in FIG. 5A, the outer diameter of the expandablemember 35 is essentially the same size as the catheter 30. The balloon35 may be inflated pneumatically or hydraulically from an externalsource, such as a syringe, to expand to a predetermined diameter, asshown in FIG. 5B.

On the outer surface of the expandable member 35, a carrier 40 may beplaced. In an embodiment, the carrier 40 may comprise a plurality ofsections 40 a or panels, which are capable of contracting into a compactform. For example, the carrier 40, in an unfolded, relaxed state, mayform the shape of a star as shown in FIG. 6. Depending on the number ofsections 40 a, the carrier 40 may assume other shapes. The carrier, forexample, may assume any suitable unfolded, relaxed state so long as thecarrier may be contracted, folded, or otherwise take a suitable form orshape for delivery to the treatment site, and be capable of expanding,enlarging, unfolding, or otherwise taking a suitable form or shape forimplantation at the treatment site. For example, in an alternativeembodiment, the carrier may be a rectangular sheet 42 having its endscurled inwardly to form a substantially cylindrical tube, as shown inFIG. 6A. The ends of the sheet 42 may be slidable relative to eachother, so as to contract or expand the cylindrical tube radially. Inother alternative embodiments, the carrier may be a radially expandabletube 44, 46, 48 of any desired shape, as shown in FIGS. 6B-6D. In theseembodiments, the expandable tube 44, 46, 48 may include at least onefoldable portion 43, 45, 47 for facilitating the radial expansion of thetube 44, 46, 48.

The carrier 40, 42, 44, 46, 48 can be configured to hold the tissueimplant in various ways. For example, FIGS. 7A-7C show cross-sectionalviews of a carrier holding a tissue implant 110 according to variousembodiments of the present invention. The tissue implant 110 embedded ina substrate 120, such as, for example, a bio-absorbable gel, and forminga patch 100 a may be placed on the outer surface of the carrier 40 asshown in FIG. 7A. Also, the carrier 40 may itself constitute a substrate120 and contain a tissue implant 110, shown FIG. 7B, so as to form apatch 100 b. It should be understood that the size of the tissue implant110 and/or the patch 100 c may vary depending upon the size and locationof the lesion to be treated, as shown in FIG. 7C.

Another embodiment of the carrier 50 according to the present inventionis shown in FIGS. 8A, 8B, and 8C. In this embodiment, the carrier 50itself forms a tissue patch comprised of a plurality of sections 50 a orpanels, similar to the embodiment shown in FIG. 7B. The carrier 50 mayform into any shape other than a star shown in FIG. 8A, similar to thepossible variations illustrated above with respect to the exemplaryembodiments of FIGS. 6 and 6A-D.

Some of the sections 50 a may be coated with bio-adhesive material 54that will hold the carrier 50 and the tissue implant 110 in contact withthe lesion. When the sections 50 a are coated with bio-adhesive material54, the sections 50 a may be arranged in such a way that when thecarrier 50 is folded, those sections 50 a holding the tissue implantcontact like sections and those sections coated with bio-adhesivematerial 54 will be in contact with a non-stick material 56, preservingthe ability to release during deployment. Similar arrangement ispossible for the carriers shown in FIGS. 6A-D.

Various materials, such as, for example, PTFE or any suitablebio-absorbable material, can be utilized to form the carrier 40. In thecase where the carrier 40 is used to place a tissue patch 100 a (e.g.,as shown in FIG. 7A) on the outer surface of the carrier 40, the carrier40 can be formed of a separable layer that can be peeled away once thematerials in the tissue patch 100 a are securely implanted. On the otherhand, in case where the carrier 40 itself forms a tissue patch (e.g. asshown in FIG. 7B), the substrate 120 may be formed of any of a number ofbio-degradable materials, such as polylactic acid (PLA), which dissolvesin vivo over a period of time, leaving only the implanted materials. Asdiscussed above, selection of material and/or composition and physicalstructure of the substrate 120 may depend on estimated degradation timeof the substrate material. This estimated degradation time maycorrespond to the time period necessary for the implanted tissues toestablish themselves. The substrate 120 may also encompass varioustherapeutic agents to promote healing process as well as bio-adhesivematerial to enhance attachment of the tissue implant to the lesion.

The delivery system may further comprise a retractable sleeve 33surrounding the carrier 40 and the tissue implant 110 to protect thetissue implant 110 and other associated materials during insertion andplacement of the catheter 30 at a lesion to be treated. The sleeve 33may be configured to retract from around the carrier 40 prior to theexpandable member 35 expanding to the expanded state, as illustrated inFIG. 5B.

As an exemplary embodiment, application of engineered tissue andassociated materials to the lower esophagus in the treatment of GERD orother disorders is described with respect to FIGS. 9 and 10. Thespecific embodiment of the present invention comprises a method fordelivering an engineered tissue implant and associated materialsendoluminally to a circumferential area near the lower esophagealjunction.

FIG. 9 shows a cross-sectional view of a delivery system with anexpandable member, e.g., a balloon 35, in deflated state during theinsertion. The carrier 40 may be tightly folded and contained in asleeve 33 to maintain a small diameter and protect the tissue implantand other associated materials, as shown in FIG. 9. The materials on thesections of the carrier 40 may be arranged to preventcross-contamination and to facilitate deployment. The tissue implant maybe arranged in such a way that, when the carrier is folded, sectionswith the tissue implant can contact with like sections and sections thatare in contact with the bio-adhesive material are coated with anon-stick gel.

FIG. 10 shows the delivery system in position for deployment in thelesion of esophagus. The delivery system may include an endoscope tovisualize the delivery process along the passageway to the lesion ofesophagus. Other suitable methods of visualization, includingfluoroscopy, may be used. Once the delivery system is in position, thesleeve 33 can be retracted or removed from around the expandable member35, and the carrier 40 can be uncovered to expose the carrier 40 and thetissue implant 110. Any conventional method known in the art may beutilized to retract or remove the sleeve 33. For example, the sleeve 33may be configured to slide down or split open to expose the carrier 40when the balloon is inflated, or may be retracted using endoscopyinstruments. The sleeve 33 may be constructed of a bio-degradablematerial that would dissolve away. Alternatively, the sleeve 33 may bemade of any material that can safely pass through the digestive tract.

FIGS. 11A-11C show the cross-sectional views of the expandable member inexemplary, representative stages of inflation within the esophagus 3,illustrating various stages of the delivery process. For illustrationpurposes only, the delivery process is illustrated with respect to theexemplary carrier 40 shown in FIG. 6. Substantially identical steps orprocesses can be used for the carriers 42, 44, 46, 48 shown in FIGS.6A-6D or any other suitable carrier. First, the delivery system is shownwith the sleeve 33 in place and the balloon 35 deflated, as shown inFIG. 11A. Next, the sleeve 33 is retracted or removed, and the balloon35 is partially inflated, allowing the carrier 40 to expand into itsintermediate shape, shown in FIG. 11B. The carrier 40 may be formed of amaterial that has a characteristic of returning to its natural shape,shown in FIG. 11B. Finally, the configuration at full inflation ofballoon 35 is shown in FIG. 11C. The carrier 40 may then have anintimate contact with the lining of the esophagus 3 and, by the use ofbio-adhesive material or any other suitable mechanism, the carrier 40and the tissue implant 10 may be fixed in place. In an alternativeembodiment, the carrier 40 may be expanded into its fully expandedposition without the intermediate step of partially inflating thecarrier 40.

The carrier 40 may also include an optional radially expanding device,such as a stent, to provide additional force against the esophagealwall. If a radially expanding device is used, the device may be removedafter a predetermined time period. Alternatively, the device may be madeof a bio-absorbable material such that it can be dissolve away after aprescribed time period.

Once the tissue implant 10 is fixed in place, the balloon 35 can bedeflated, leaving the carrier 40 and implant materials 10 fixed to theluminal wall 4. The choice of carrier substrate material will determinewhether further intervention will be necessary to remove the leftoversubstrate material, once the cell colonies are established.

According to another exemplary embodiment, if a tissue implant is to beattached to a relatively small lesion, a smaller tissue patch, such as,for example, the tissue patches shown in FIGS. 2 and 3, can be used. Asmaller tissue patch can be placed on a portion of the carrier 40 orexpandable member 35 for delivery. An adhesive sheet, a stent, agrasper, or any other suitable mechanism can optionally be used tofacilitate accurate delivery of the tissue patch. The remaining steps ofdelivery are substantially identical to the steps described above.

For the purpose of explaining a function of the tissue patches 10, across-section through a region of the esophagus containing abnormalepithelium 20, e.g., Barrett's Epithelium, is shown in FIG. 12A. It isoften necessary to surgically remove the diseased tissue 20. However,after a resection of the diseased tissue 20 has been performed, a largeopening 22 is left in the esophagus 3. For illustration purposes only,it is assumed that the disease (e.g., abnormal epithelium 20) affectedthe mucosa layer 25 and submucosa layer 26, as shown in FIG. 12B. Inthis condition, the muscularis layer 27 above the serosa layer 28 of theesophagus 3 is exposed to the harsh environment of the lower esophagus21.

FIG. 12C shows how the endoluminal tissue patch 10 of the presentinvention, delivered to the site 22 endoluminally through an overtube orendoscope, would be used to fill and protect the region of exposedmuscularis layer 27. The bottom surface 17 a of the tissue patch may beplaced in contact with the muscularis layer 27 while the top surface 18a faces toward the lumen of the esophagus 3. The bio-absorbable gellayer 16 that covers the top of the tissue implant can be made thickerto ensure that it will last, for example, several days, serving toprotect the tissue implant 11 a from the harsh chemistry of the loweresophagus 3. The thinner bio-absorbable gel layer 15 on the bottomsurface of the tissue implant 11 a may only last long enough to protectthe tissue implant 11 during its deployment to the treatment site 22. Inaddition, the bio-absorbable gel 12 could be infused with any of anumber of therapeutic agents, such as, for example, Human Growth Hormone(HGH), genetically engineered cells, antibiotics, analgesics oranaesthetics, and/or pH sensitive or reactive chemistry. Over time, asthe bio-absorbable gel is absorbed, these chemistries would be releasedinto the site, promoting cell growth in the tissue patch and thesurrounding esophageal tissue, relieving pain, preventing infection, andhastening the healing process. FIG. 12D illustrates the fully healedsite. These therapeutic agents may be provided in layers such that eachof the chemical agents can be activated at a predetermined time duringthe treatment process in a controlled manner.

Although the present invention is depicted in this disclosure as beingused in the treatment of wounds in the esophagus of a patient withBarrett's Esophagus, it is understood that the endoluminal delivery andthe tissue patches according to the present invention could be used totreat any of a number of different disease conditions in the alimentarytract. Examples of this would be in the treatment of gastric or duodenalulcers or to promote healing at sites of surgical resection ofgastrointestinal polyps or tumors. Furthermore, it is also to beunderstood that the tissue implant may be replaced with any other typeof cells depending on its use, e.g., vascular endothelial cells such asxenografts, allografts, or autografts.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1-36. (canceled)
 37. A system for delivering a tissue implant to alesion in an alimentary tract of a patient, comprising: a catheterhaving an expandable member at a distal end portion; and a carrierhaving an outer surface and an inner surface and placed around theexpandable member, the carrier configured to expand from a contractedstate to an expanded state and to receive the tissue implant, whereinthe tissue implant contacts the lesion of the alimentary tract when theexpandable member expands the carrier to the expandable state.
 38. Asystem according to claim 37, further comprising a retractable sleevesurrounding the carrier to protect the carrier during insertion andplacement of the catheter, the sleeve configured to retract from aroundthe carrier prior to the expandable member expanding to the expandedstate.
 39. A system according to claim 37, wherein the carrier is formedof a plurality of sections which are configured to be folded in thecontracted state.
 40. A system according to claim 39, wherein at leastone of the plurality of panels comprises bio-adhesive material.
 41. Asystem according to claim 39, wherein the carrier constitutes asubstrate in which the tissue implant is embedded.
 42. A systemaccording to claim 39, wherein the tissue implant is placed on the outersurface of the carrier and configured to be folded together with theplurality of sections in the contracted state.
 43. A system according toclaim 41, wherein the tissue implant is embedded in a substrate to forma tissue patch on the outer surface of the carrier.
 44. A systemaccording to claim 43, wherein the substrate is a bio-absorbable gel.45. A system according to claim 41, wherein the tissue implant isembedded in the substrate in a form of a cellular suspension.
 46. Asystem according to claim 43, wherein the carrier is configured to bepeeled away from the tissue patch once the tissue patch is securelyplaced.
 47. A system according to claim 37, wherein the carrier is madeof bio-absorbable material which dissolves over a period of time.
 48. Asystem according to claim 37, wherein the tissue implant is anengineered tissue.
 49. A method of delivering a tissue implant to alesion in a patient's body, comprising: providing a catheter having anexpandable member at a distal end portion; disposing a contractedcarrier around the expandable member, the carrier configured to expandto an expanded state and containing the tissue implant; inserting thecatheter and the contracted carrier into a lumen containing the lesion;positioning the carrier and expandable member at the lesion; andexpanding the expandable member so as to expand the carrier to theexpanded state to implant the tissue implant into the lesion.
 50. Amethod according to claim 49, further comprising providing a retractablesleeve which surrounds the folded carrier to protect the folded carrierduring insertion of the catheter, wherein the retractable sleeve isconfigured to retract from around the carrier prior to the expandablemember expanding to the expanded state.
 51. A method according to claim49, wherein the carrier is formed of a plurality of sections which areconfigured to be folded in the contracted state.
 52. A method accordingto claim 51, wherein at least a portion of the plurality of sectionsinclude bio-adhesive material.
 53. A method according to claim 51,wherein the carrier constitutes a substrate in which the tissue implantis embedded.
 54. A method according to claim 51, wherein the tissueimplant is placed on the outer surface of the carrier and configured tobe contracted with the plurality of sections in the contracted state.55. A method according to claim 54, wherein the tissue implant isembedded in a substrate to form a tissue patch on the outer surface ofthe carrier.
 56. A method according to claim 55, wherein the substrateis a bio-absorbable gel.
 57. A method according to claim 53, wherein thetissue implant is embedded in the substrate in a form of a cellularsuspension.
 58. A method according to claim 49, wherein the carrier isconfigured to be peeled away from the tissue patch once the tissue patchis securely placed.
 59. A method according to claim 49, wherein thecarrier is made of bio-absorbable material which dissolves over a periodof time.
 60. A method according to claim 49, wherein the tissue implantis an engineered tissue.